How many Founding Fathers were themselves held in slavery?

A couple of years ago, I came across and wrote about an article in Ebony magazine on the topic of white slavery.

This highlights yet another miscarriage of fake historians. We are all supposed to collectively shrug our shoulders, wave our hand and say "oh but that was just 'indentured servitude'. That wasn't real slavery." As the Ebony article makes clear, yes, it was very much "just as real" as the slavery we are all constantly made to feel guilty for.

But I've already written what I wanted about that article. Here's the real question:

How many of the Founding Fathers themselves were held in slavery? We know whites were held in bondage by the King. We know it happened well before America was founded. So who?

There were two, in particular, both of whom were signatories of the Declaration of Independence.

The first is Matthew Thornton, and the second is George Taylor.

(Source), (source), (source)

https://tinyurl.com/ya53jztj